GLOSSAEY. 



405 



Sph.erella Tlilasnei (black of cereals). 

 - — In moist weather cereals become covered 

 with black spots. The fungus cladosporium, 

 which produces this disease, shows itself very 

 commonly on the dead parts of very <Urt"erent 

 plants, and it lives generally as a saprophyte. 

 The black of cereals may cause rather gi'eat 

 damage, the leaves wither and turn grey, 

 the stalks die without producing ears. 



Tenthredo (saw-fly I ok the Turnip. 

 Athalia Spinarun. — The larva of this 

 saw-tiy attacks the turnip, it gnaws the 

 parenchyma of the leaves. Two annual 

 generations — June and September. 



Tetranychus telarius (red spider). — 

 A red, polyphagous acarus, it attacks the 

 most diverse plants, chiefly trees, haricots, 

 peas, clover, pumpkins, beets, hemp, hops, 

 roses, limes, chestnuts, willows, and fruit 

 trees. It produces the same symptoms on 

 all these plants. The leaves, prematurely 

 discoloured, become copper yellow or red, 

 and eventually wither, to fall before the 

 end of summer. The under surfaces of these 

 leaves are covered with a very fine light 

 tissue and white pellicles, in the midst of 

 which the red acarus moves. If the trees 

 be examined, the limes for example, deprived 

 in this way of their leaves, the branches are 

 found covered with a silky tissue containing 

 thousands of acari. These acari are accus- 

 tomed to quit the leaves in autumn, and to 

 hide themselves round the buds to pass tlie 

 winter ; they even often attack these, and 

 deform them up to the moment of their 

 exodus in the month of May, towards the 

 young leaves produced by the healthy buds. 

 The constant irritation, produced on the 

 leaf by the rostrum of these acari, excite the 

 cells, which multiply abnormally and pro- 

 duce characteristic deformations, brown 

 rust, erinoses, galls, etc., forming propitious 

 shelters for tltese acari. They produce on 

 kitchen garden plants and on fruit trees the 

 disease known by gardeners as Grise and the 

 Red disease of the vine. 



Thrips of Cereals. Thrips Cerealium. 

 — This hemiptera of 2 millimetres is a 

 dangerous parasite. The larvaa attack the 

 ears of wheat, rye, and barley, where tiiey 

 suck the newly formed grains, and stop their 

 development. Tlie adults, crawling always 

 on the most tender leaves of the plant, suck 

 them and wither them. Its damages, it 

 appears, are not confined to cereals ; the 

 thrips likewise attacks straw! terries, peas, etc. 



Tinea. — Small niotlis distinguished by 

 long antenna, narrow and pointed at their ex- 

 tremities, and by large fringes which line the 

 periphery of their wings, especially the lower 

 wings. The caterpillars, known under the 

 vulgar name of mites, commit serious havoc. 



Tinea of Flouh. Asopia farinalis.— 

 Butterfly of 24-2.T millimetres from tip to 

 tip. Upper wings yellow in the midille, 

 and brown at the summit and the base. 

 The lower wings grey, with two bright lines. 

 The caterpillars live in flour and bran. 



Tinea of Grain. Tinea ffranella.— The 

 tinea of grain is a butterfly a little larger 

 than tlie preceding. It causes damage dur- 



ing the first fortnight of August. The female 

 seeks the wheat granaries, there to lay its 

 eggs on the grain. The caterpillars, known 

 as the white-worm of wheat, hatch in eight 

 to ten days and attai-k several grains at a 

 time, uniting them Ity a ti.ssue, in the shelter 

 of winch thev gnaw them on the outside. 



TiNGis PIRI. Ti:/rr „f the Pear-tree.— 

 This brown flat hemiptera, 3 millimetres in 

 length, appears in June. Larvre, grubs, and 

 adults live as one family on the lower sur- 

 face of the leaf or the young shoots, and 

 riddle them with their pricks. The young 

 shoots wither and the leaves brown. The 

 tiger preferably attacks pear-trees grown on 

 an espalier, and its depre<lations are most 

 terrible in August and Septemlier. 



TiPDLA OLERACEA (me;idow tipula). TlPU- 

 i;A PRATENSIS (garden tipula). — The tipulse 

 resemble large gnats with long legs ; the 

 body is grey, highly elongated. They are 2 

 centimetres long. They may be seen flying 

 above meadows in summer. These large 

 mosquitos lay their eggs in June in the soil. 

 The larvte, wliich liatch in eight days, live 

 underground, where tliey attack the radicles 

 of kitchen garden plants and ornamental 

 plants. They are particularly injurious to 

 meadows, to grass plots, and to cereals, of 

 which they not onl}' attack the roots, but 

 also the leaves in the spring (Ritzenia Bos). 



Tylenchus tritici ("ear cockles," 

 "purples," "false ergot," galls of wheat, 

 eel-worms of wheat). — 'i"he eel -worm of wheat 

 is a very small filiform worm with a smooth 

 tegument which twists its body like an eel, 

 hence the name given to it ; length -3 milli- 

 metres. The ears attacked in place of 

 ordinary grain have small, rounded, blacki.sh 

 grains like smutty grains. If a section be 

 made of one of these grains there will be 

 seen under the hard, thick shell a white 

 farinaceous mass consisting of thousands- of 

 small anguillulides in a dormant state of life 

 and perfectly immoliile. A little moisture 

 suffices to awake them, which invariably 

 comes when the smutty grain is sown. 

 These eel-worms may preserve their vitality 

 for two and a half years in the grain. Once 

 they issue from their home they iu.stal 

 themselves on the young plants, ascending 

 as the stem rises ; reaching the young ears 

 they penetrate the still milky grains where 

 the females deposit tlieir progeny. The.se 

 small microscopic worm.s cause the disease 

 known as earcockles. In the spring when the 

 young stems of spring wheat are infested 

 with eels the leaves are goffered and folded, 

 the plant, in.stead of growing in height, 

 tillers. 



Urocystes cepul^ (smut of the onion). — 

 Tliis smut causes considerable havoc in 

 America. It has been observed in France 

 by Cornu. It attacks tlie bulbs of the 

 onion when very young and kills them. Its 

 presence is indicated by obscure spots on the 

 leaves of the yoimg onion, whilst in germina- 

 tion the leaves split longitudinally and show 

 a withered tissue covered with black dust. 

 The smutty spots afterwards extend on the 

 bull) and invade it at its base. 



